Key Concepts: The somatic neuromuscular junction is the site of communication between motor neurons and skeletal muscle fibres. Specialisations of the neuromuscular junction mean that activity in and release of transmitter from motor neurons produces contraction of skeletal muscle fibres rapidly and reliably.he neuromuscular junction comprises four cell types: the motor neuron, terminal Schwann cell, skeletal muscle fibre and kranocyte, with the motor neuron and muscle fibre separated by a gap called the synaptic cleft.
Causes. Headaches can be triggered by a variety of factors. The most common cause of headaches is prolonged tension or stress. These are called tension headaches or muscle-contraction headaches. Virtually everyone suffers from this at some time. Muscles in your scalp, neck, and face tighten and contract, causing spasms and pain.
Some of the more common triggers for headache are lifestyle related, such as poor diet, stress, muscle tension, and lack of exercise. Serious underlying disorders, such as brain tumours, are rarely the cause of headache, although persistent headache should always be investigated by a doctor. Headache can be classified into two broad categories: primary and secondary. Examples of primary headache include cluster and tension headaches.